Frozen Pipes During an Outage: Prevention and What to Do

In a winter outage, frozen pipes are one of the most expensive problems you can have. A pipe freezes, the ice expands, the pipe splits, and nothing happens until it thaws. Then water pours into your walls, floors and basement, often while you're not home. Here's how to prevent it.

01Where pipes freeze first

• Pipes on exterior walls, especially in kitchens and bathrooms.
• Pipes in unheated spaces: crawlspaces, garages, attics, and basements near rim joists.
• Outdoor faucets and the lines feeding them.
• Pipes near drafty spots: dryer vents, foundation cracks, sill plates.

02Before winter

• Know where your main water shutoff is, and make sure it turns. Tag it.
• Insulate exposed pipes in crawlspaces, garages and basements with foam pipe insulation.
• Seal drafts near pipes with caulk or spray foam.
• Shut off and drain outdoor faucets, and disconnect hoses.
• Know how to drain your water heater and where the drain valve is.

03When the power goes out

If the house is losing heat:

1. Open cabinet doors under sinks on exterior walls so warmer room air reaches the pipes.
2. Let faucets drip, both hot and cold, on the sinks most at risk. Moving water is harder to freeze, and a drip relieves pressure if a pipe does start to freeze.
3. Keep the house as warm as you safely can. See heating your home without power, safely.
4. Keep the garage door closed if there are pipes in the garage.

These buy time. In a very cold, very long outage, they're not enough.

04If it's going to be a long, cold outage: drain the house

If the house is going to drop below freezing and stay there, or you're leaving, draining the plumbing protects it:

1. Shut off the main water valve.
2. Turn off the water heater: the power at the breaker for an electric unit, or set a gas unit to "pilot" or "off" per its instructions.
3. Open every faucet, starting at the top floor and working down, hot and cold. Open the lowest faucet (often a basement sink or an outdoor spigot) last to let the water drain out.
4. Flush toilets to empty the tanks. Bail or sponge out what's left in the bowl, or add RV/plumbing antifreeze (not car antifreeze) to the bowls and traps.
5. Drain the water heater if the house will freeze, using a hose to a floor drain or outside. Let it cool first; it's hot.
6. Don't forget: a dishwasher, washing machine, water softener, and any well pressure tank need attention too.

If you have a boiler or a hot-water heating system, it's a more complicated job. Call a plumber if you can.

Before you drain the water heater, think about using that water: a water heater holds tens of gallons of drinkable water. See your water heater is an emergency water tank.

05Thawing a frozen pipe

If water stops coming out of a faucet or only trickles:

• Keep the faucet open.
• Warm the pipe with a hair dryer, a heating pad, or towels soaked in hot water, starting near the faucet and working back.
• Never use an open flame (torch, propane heater) on a pipe. It's a fire risk and can make steam that bursts the pipe.
• If you can't find the frozen spot or can't reach it, call a plumber.

06When the power comes back

Check every pipe, especially the ones in the cold spots, as the house warms up. Look and listen for leaks. If a pipe burst, shut off the main water right away.

07Your sump pump

Don't forget the sump pump: a thaw after a winter storm can bring water in, and the pump doesn't run without power. See keeping the sump pump running in an outage.

Related: Midwest Power Outages: How Long They Really Last (NIPSCO's August Storm)